The invention relates to a method for creating markings, in particular marking lines of highly viscous marking material, in particular a two-component cold plastic, on a surface, which is to be marked, in particular a road surface, wherein the marking material is discharged from a material supply and, before striking the surface, which is to be marked, is fed to a rotational body, which moves relative to the surface in longitudinal direction of the marking, which is to be created, and is applied to the surface so as to be divided into unequal material portions by means of said rotational body, wherein the axis of rotation of the rotational body runs at right angles to the longitudinal direction of the marking and wherein the marking material is fed to the rotational body in the form of a plurality of marking material flows, which, viewed in longitudinal direction of the rotational body, are discharged next to one another.
In addition, the invention relates to a device for creating markings, in particular marking lines of highly viscous marking material, in particular a two-component cold plastic, on a surface, which is to be marked, in particular a road surface, comprising at least one material storage container, comprising at least one conveying device for conveying marking material from the material storage container to a material outlet and comprising a rotational body, which is arranged below the material outlet and through which marking material, which flows from the material outlet, can be divided into unequal material portions and can be applied to the surface, wherein, during operation, the device can be moved relative to the surface in longitudinal direction of the marking, which is to be created, and wherein the axis of rotation of the rotational body runs at right angles to the longitudinal direction of the marking and wherein the marking material can be fed to the rotational body in the form of a plurality of marking material flows, which, viewed in longitudinal direction of the rotational body, flow next to one another.
Structured markings of unequal material portions, thus comprising a stochastic material distribution, encompass increased traffic safety, in particular in the dark and in response to wetness, because rain water can drain and individual areas of the marking protrude from the water film on the road surface. The light from automobile headlights is reflected better through this. In addition, a lower noise development when driving over such markings is advantageous as compared to markings of equal material drops, which are arranged regularly. In the case of markings comprising a stochastic material distribution, the risk that the marking material comes loose when a snowplow drives over it, is also small.
A method and a device of the above-mentioned type are known from document EP 0 665 062 A1. This document shows a device on a vehicle for marking the road by means of color drops. The device has a storage container for color mass, which, on the bottom, encompasses an outlet gap, to which a guide plate, which runs diagonally to the bottom area of the storage container and on which a laminar flow of the color mass takes place, connects. On its bottom edge, the guide plate is provided with notches, which ensure that a plurality of color mass partial flows is created, when the vehicle moves in operating direction. A turbine roller comprising blades for creating an air flow, which acts on the color mass partial flows that drain from the guide plate, is located below the bottom of the storage container. This air flow divides the color mass into color drops and accelerates the color drops, which are flung onto the road surface with great force.
It is considered to be a disadvantage in this state of the art that the volume flow of the color mass from the open storage container through the outlet gap strongly depends on the level of the color mass in the open storage container and fluctuates with this level. The material viscosity, which also fluctuates due to temperature changes, also influences the discharged color mass quantity. As a result, the quantity of the color mass, which is discharged for each unit of stretch of road, which the vehicle covers, is not constant. This leads to irregular road markings, which means a reduced quality. In addition, the marking speed, which can be reached, is limited, because the color mass is dispensed from the storage container solely by means of the force of gravity. This state of the art furthermore encompasses the disadvantage that the marking process needs to be interrupted at relatively short intervals as a function of the hardening time of the marking material, so as to clean the device parts touched by the marking material, in particular the storage container and the guide plate. This means lower daily outputs and a high flushing fluid consumption, which leads to high costs and to environmental pollution. In the case of the slot-shaped material outlet, the material flow can furthermore be hindered easily, e.g. because clumps get caught in the slot, which requires a relatively frequent cleaning of the outlet.
A further method and a device for the above-mentioned purpose are known from document CH 681 904 A5. The device forms an open system herein, comprising a draw box comprising a slot-shaped material outlet and comprising a rotational body arranged therebelow, here in the shape of a roller made of a material having a low adhesiveness. When producing the marking, the marking material, which flows out in the form of a thin curtain, is divided into a plurality of unequally large and irregularly shaped material portions by means of the rotating rotational body, prior to striking the surface, which is to be marked. Structured markings comprising a stochastic material distribution can be created in this manner.
In addition to the above-mentioned disadvantages, this state of the art encompasses the further disadvantage that the marking material, which is applied herein in the form of a flat belt or curtain, has the characteristic that, due to acceleration caused by the force of gravity and wall friction at the outlet walls, the material flow is constricted after leaving the slot-shaped outlet prior to striking the rotational body. The effect of constriction is a function of the material viscosity, among others, which also fluctuates due to temperature changes, and of the type and number of the fillers and solids, which are added to the marking material. As a result, the line width of the marking line is thus always smaller than the slot width of the outlet to an extent, which cannot be determined accurately ahead of time.
A further device is known from document EP 0 148 494 A2. Drops made of marking material are discharged from gap-shaped outlets, which are oriented substantially horizontally and which are arranged next to one another and which are separated from one another by means of separating walls, and are spun onto the surface, which is to be marked, by means of a rotating paddle arrangement. The axis of rotation of the paddle arrangement is thereby located at the same height as the outlets. Marking lines of individual material drops, which are largely identical, can be created with this.
It is considered to be disadvantageous in the case of this state of the art that the marking material, which adheres to the separating walls and which hardens at that location, can relatively easily lead to impairments of the movement of the rotating paddles. A cleaning of the relatively narrow outlets is difficult and time-consuming. Structured markings comprising a stochastic material distribution cannot be created by means of this device.
A device for creating marking lines, which consist of a plurality of individual marking material portions, is known from document DE 10 2009 045 576 A1. The marking material portions herein can be ejected from a nozzle arrangement, which is connected to a marking material source and which comprises a plurality of discharge nozzles, which are arranged at right angles to a direction of movement of the device, by means of blasts of compressed air. Marking lines of individual material drops, which are largely identical, can be created with this, whereas structured markings comprising a stochastic material distribution, however, cannot be created with this.
The instant invention thus has the task of creating a method and a device of the above-mentioned type, which avoids the specified disadvantages and which makes it possible to produce structured markings comprising a stochastic material distribution, of high quality and in a highly cost-efficient manner.